A few things to consider :
You don't have to open the package for them to charge you with it. If you come in contact with it, that includes writing RETURN TO SENDER on it, that is all they need.
The only people getting busted on the property of the post office are the ones that use P.O. Boxes. If you have a street address that it is going to, they are not going to call you down to the post office to bust you. They are going to bust you at home. Why? Because that increases the chance of them finding additional things to charge you with. Guns, rec drugs, hot cable boxes, INFORMATION ABOUT THE ROID GAME, whatever else. The reason they do this is because smart guys know that unless they have been charged/arrested of a crime before, they will cop a First Offender's Plea which gurantees you no jail time. (although some cases like rape, murder, etc.. First Offender is not given as an option.) So they bust you at home, you might escape the possession/distribution charge, but they land some more charges on you for weapons, recs, etc... and you are not going to be given many other alternatives. The more they charge you with the stronger the case. The law works in ways that benefit them. Not you.
And keep in mind that they don't have to bust you right away, they can keep that evidence for on down the road. When they get close to nailing someone big and they need the final nail in the coffin. That is when you are rounded up at 5AM in the morning and taken to the station and told "14 months ago you received a package from XXXXXXXX that contained XXXXXXX and XXXXXXX in these quantities..(pulls out photographs and sheets)..." That's when they start in with "it can all go away if you do this...." type of shit.
So let's be reasonable. People beat on their chests and cry about "I won't ever snitch". That's bullshit. The only people that don't snitch are the ones who don't have the option cause the cops don't need their cooperation. They wait until the time is right, you just got married, you are currently in a divorce/child custody fight, you lost your job, etc... then they come knocking and your ass doesn't have a chance to consider anything else.
So take a good look in the mirror and ask yourself are you really being as safe as you possibly can? Is the potential trouble worth doing this for when most of you won't even achieve a physique good enough for International Male no matter how much shit you use?
Hmmm... makes you wonder huh?